mbedtls/programs/ssl/dtls_server.c
Ryan LaPointe dbb192d157 Fix inaccurate comment in sample DTLS server
Signed-off-by: Ryan LaPointe <ryan@ryanlapointe.org>
2021-03-15 16:43:27 -04:00

439 lines
12 KiB
C

/*
* Simple DTLS server demonstration program
*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#include <stdio.h>
#include <stdlib.h>
#define mbedtls_printf printf
#define mbedtls_fprintf fprintf
#define mbedtls_time_t time_t
#define mbedtls_exit exit
#define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
#define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
#endif
/* Uncomment out the following line to default to IPv4 and disable IPv6 */
//#define FORCE_IPV4
#ifdef FORCE_IPV4
#define BIND_IP "0.0.0.0" /* Forces IPv4 */
#else
#define BIND_IP "::"
#endif
#if !defined(MBEDTLS_SSL_SRV_C) || !defined(MBEDTLS_SSL_PROTO_DTLS) || \
!defined(MBEDTLS_SSL_COOKIE_C) || !defined(MBEDTLS_NET_C) || \
!defined(MBEDTLS_ENTROPY_C) || !defined(MBEDTLS_CTR_DRBG_C) || \
!defined(MBEDTLS_X509_CRT_PARSE_C) || !defined(MBEDTLS_RSA_C) || \
!defined(MBEDTLS_CERTS_C) || !defined(MBEDTLS_PEM_PARSE_C) || \
!defined(MBEDTLS_TIMING_C)
int main( void )
{
printf( "MBEDTLS_SSL_SRV_C and/or MBEDTLS_SSL_PROTO_DTLS and/or "
"MBEDTLS_SSL_COOKIE_C and/or MBEDTLS_NET_C and/or "
"MBEDTLS_ENTROPY_C and/or MBEDTLS_CTR_DRBG_C and/or "
"MBEDTLS_X509_CRT_PARSE_C and/or MBEDTLS_RSA_C and/or "
"MBEDTLS_CERTS_C and/or MBEDTLS_PEM_PARSE_C and/or "
"MBEDTLS_TIMING_C not defined.\n" );
mbedtls_exit( 0 );
}
#else
#if defined(_WIN32)
#include <windows.h>
#endif
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include "mbedtls/entropy.h"
#include "mbedtls/ctr_drbg.h"
#include "mbedtls/certs.h"
#include "mbedtls/x509.h"
#include "mbedtls/ssl.h"
#include "mbedtls/ssl_cookie.h"
#include "mbedtls/net_sockets.h"
#include "mbedtls/error.h"
#include "mbedtls/debug.h"
#include "mbedtls/timing.h"
#if defined(MBEDTLS_SSL_CACHE_C)
#include "mbedtls/ssl_cache.h"
#endif
#define READ_TIMEOUT_MS 10000 /* 10 seconds */
#define DEBUG_LEVEL 0
static void my_debug( void *ctx, int level,
const char *file, int line,
const char *str )
{
((void) level);
mbedtls_fprintf( (FILE *) ctx, "%s:%04d: %s", file, line, str );
fflush( (FILE *) ctx );
}
int main( void )
{
int ret, len;
mbedtls_net_context listen_fd, client_fd;
unsigned char buf[1024];
const char *pers = "dtls_server";
unsigned char client_ip[16] = { 0 };
size_t cliip_len;
mbedtls_ssl_cookie_ctx cookie_ctx;
mbedtls_entropy_context entropy;
mbedtls_ctr_drbg_context ctr_drbg;
mbedtls_ssl_context ssl;
mbedtls_ssl_config conf;
mbedtls_x509_crt srvcert;
mbedtls_pk_context pkey;
mbedtls_timing_delay_context timer;
#if defined(MBEDTLS_SSL_CACHE_C)
mbedtls_ssl_cache_context cache;
#endif
mbedtls_net_init( &listen_fd );
mbedtls_net_init( &client_fd );
mbedtls_ssl_init( &ssl );
mbedtls_ssl_config_init( &conf );
mbedtls_ssl_cookie_init( &cookie_ctx );
#if defined(MBEDTLS_SSL_CACHE_C)
mbedtls_ssl_cache_init( &cache );
#endif
mbedtls_x509_crt_init( &srvcert );
mbedtls_pk_init( &pkey );
mbedtls_entropy_init( &entropy );
mbedtls_ctr_drbg_init( &ctr_drbg );
#if defined(MBEDTLS_DEBUG_C)
mbedtls_debug_set_threshold( DEBUG_LEVEL );
#endif
/*
* 1. Load the certificates and private RSA key
*/
printf( "\n . Loading the server cert. and key..." );
fflush( stdout );
/*
* This demonstration program uses embedded test certificates.
* Instead, you may want to use mbedtls_x509_crt_parse_file() to read the
* server and CA certificates, as well as mbedtls_pk_parse_keyfile().
*/
ret = mbedtls_x509_crt_parse( &srvcert, (const unsigned char *) mbedtls_test_srv_crt,
mbedtls_test_srv_crt_len );
if( ret != 0 )
{
printf( " failed\n ! mbedtls_x509_crt_parse returned %d\n\n", ret );
goto exit;
}
ret = mbedtls_x509_crt_parse( &srvcert, (const unsigned char *) mbedtls_test_cas_pem,
mbedtls_test_cas_pem_len );
if( ret != 0 )
{
printf( " failed\n ! mbedtls_x509_crt_parse returned %d\n\n", ret );
goto exit;
}
ret = mbedtls_pk_parse_key( &pkey, (const unsigned char *) mbedtls_test_srv_key,
mbedtls_test_srv_key_len, NULL, 0 );
if( ret != 0 )
{
printf( " failed\n ! mbedtls_pk_parse_key returned %d\n\n", ret );
goto exit;
}
printf( " ok\n" );
/*
* 2. Setup the "listening" UDP socket
*/
printf( " . Bind on udp/*/4433 ..." );
fflush( stdout );
if( ( ret = mbedtls_net_bind( &listen_fd, BIND_IP, "4433", MBEDTLS_NET_PROTO_UDP ) ) != 0 )
{
printf( " failed\n ! mbedtls_net_bind returned %d\n\n", ret );
goto exit;
}
printf( " ok\n" );
/*
* 3. Seed the RNG
*/
printf( " . Seeding the random number generator..." );
fflush( stdout );
if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy,
(const unsigned char *) pers,
strlen( pers ) ) ) != 0 )
{
printf( " failed\n ! mbedtls_ctr_drbg_seed returned %d\n", ret );
goto exit;
}
printf( " ok\n" );
/*
* 4. Setup stuff
*/
printf( " . Setting up the DTLS data..." );
fflush( stdout );
if( ( ret = mbedtls_ssl_config_defaults( &conf,
MBEDTLS_SSL_IS_SERVER,
MBEDTLS_SSL_TRANSPORT_DATAGRAM,
MBEDTLS_SSL_PRESET_DEFAULT ) ) != 0 )
{
mbedtls_printf( " failed\n ! mbedtls_ssl_config_defaults returned %d\n\n", ret );
goto exit;
}
mbedtls_ssl_conf_rng( &conf, mbedtls_ctr_drbg_random, &ctr_drbg );
mbedtls_ssl_conf_dbg( &conf, my_debug, stdout );
mbedtls_ssl_conf_read_timeout( &conf, READ_TIMEOUT_MS );
#if defined(MBEDTLS_SSL_CACHE_C)
mbedtls_ssl_conf_session_cache( &conf, &cache,
mbedtls_ssl_cache_get,
mbedtls_ssl_cache_set );
#endif
mbedtls_ssl_conf_ca_chain( &conf, srvcert.next, NULL );
if( ( ret = mbedtls_ssl_conf_own_cert( &conf, &srvcert, &pkey ) ) != 0 )
{
printf( " failed\n ! mbedtls_ssl_conf_own_cert returned %d\n\n", ret );
goto exit;
}
if( ( ret = mbedtls_ssl_cookie_setup( &cookie_ctx,
mbedtls_ctr_drbg_random, &ctr_drbg ) ) != 0 )
{
printf( " failed\n ! mbedtls_ssl_cookie_setup returned %d\n\n", ret );
goto exit;
}
mbedtls_ssl_conf_dtls_cookies( &conf, mbedtls_ssl_cookie_write, mbedtls_ssl_cookie_check,
&cookie_ctx );
if( ( ret = mbedtls_ssl_setup( &ssl, &conf ) ) != 0 )
{
printf( " failed\n ! mbedtls_ssl_setup returned %d\n\n", ret );
goto exit;
}
mbedtls_ssl_set_timer_cb( &ssl, &timer, mbedtls_timing_set_delay,
mbedtls_timing_get_delay );
printf( " ok\n" );
reset:
#ifdef MBEDTLS_ERROR_C
if( ret != 0 )
{
char error_buf[100];
mbedtls_strerror( ret, error_buf, 100 );
printf("Last error was: %d - %s\n\n", ret, error_buf );
}
#endif
mbedtls_net_free( &client_fd );
mbedtls_ssl_session_reset( &ssl );
/*
* 3. Wait until a client connects
*/
printf( " . Waiting for a remote connection ..." );
fflush( stdout );
if( ( ret = mbedtls_net_accept( &listen_fd, &client_fd,
client_ip, sizeof( client_ip ), &cliip_len ) ) != 0 )
{
printf( " failed\n ! mbedtls_net_accept returned %d\n\n", ret );
goto exit;
}
/* For HelloVerifyRequest cookies */
if( ( ret = mbedtls_ssl_set_client_transport_id( &ssl,
client_ip, cliip_len ) ) != 0 )
{
printf( " failed\n ! "
"mbedtls_ssl_set_client_transport_id() returned -0x%x\n\n", (unsigned int) -ret );
goto exit;
}
mbedtls_ssl_set_bio( &ssl, &client_fd,
mbedtls_net_send, mbedtls_net_recv, mbedtls_net_recv_timeout );
printf( " ok\n" );
/*
* 5. Handshake
*/
printf( " . Performing the DTLS handshake..." );
fflush( stdout );
do ret = mbedtls_ssl_handshake( &ssl );
while( ret == MBEDTLS_ERR_SSL_WANT_READ ||
ret == MBEDTLS_ERR_SSL_WANT_WRITE );
if( ret == MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED )
{
printf( " hello verification requested\n" );
ret = 0;
goto reset;
}
else if( ret != 0 )
{
printf( " failed\n ! mbedtls_ssl_handshake returned -0x%x\n\n", (unsigned int) -ret );
goto reset;
}
printf( " ok\n" );
/*
* 6. Read the echo Request
*/
printf( " < Read from client:" );
fflush( stdout );
len = sizeof( buf ) - 1;
memset( buf, 0, sizeof( buf ) );
do ret = mbedtls_ssl_read( &ssl, buf, len );
while( ret == MBEDTLS_ERR_SSL_WANT_READ ||
ret == MBEDTLS_ERR_SSL_WANT_WRITE );
if( ret <= 0 )
{
switch( ret )
{
case MBEDTLS_ERR_SSL_TIMEOUT:
printf( " timeout\n\n" );
goto reset;
case MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY:
printf( " connection was closed gracefully\n" );
ret = 0;
goto close_notify;
default:
printf( " mbedtls_ssl_read returned -0x%x\n\n", (unsigned int) -ret );
goto reset;
}
}
len = ret;
printf( " %d bytes read\n\n%s\n\n", len, buf );
/*
* 7. Write the 200 Response
*/
printf( " > Write to client:" );
fflush( stdout );
do ret = mbedtls_ssl_write( &ssl, buf, len );
while( ret == MBEDTLS_ERR_SSL_WANT_READ ||
ret == MBEDTLS_ERR_SSL_WANT_WRITE );
if( ret < 0 )
{
printf( " failed\n ! mbedtls_ssl_write returned %d\n\n", ret );
goto exit;
}
len = ret;
printf( " %d bytes written\n\n%s\n\n", len, buf );
/*
* 8. Done, cleanly close the connection
*/
close_notify:
printf( " . Closing the connection..." );
/* No error checking, the connection might be closed already */
do ret = mbedtls_ssl_close_notify( &ssl );
while( ret == MBEDTLS_ERR_SSL_WANT_WRITE );
ret = 0;
printf( " done\n" );
goto reset;
/*
* Final clean-ups and exit
*/
exit:
#ifdef MBEDTLS_ERROR_C
if( ret != 0 )
{
char error_buf[100];
mbedtls_strerror( ret, error_buf, 100 );
printf( "Last error was: %d - %s\n\n", ret, error_buf );
}
#endif
mbedtls_net_free( &client_fd );
mbedtls_net_free( &listen_fd );
mbedtls_x509_crt_free( &srvcert );
mbedtls_pk_free( &pkey );
mbedtls_ssl_free( &ssl );
mbedtls_ssl_config_free( &conf );
mbedtls_ssl_cookie_free( &cookie_ctx );
#if defined(MBEDTLS_SSL_CACHE_C)
mbedtls_ssl_cache_free( &cache );
#endif
mbedtls_ctr_drbg_free( &ctr_drbg );
mbedtls_entropy_free( &entropy );
#if defined(_WIN32)
printf( " Press Enter to exit this program.\n" );
fflush( stdout ); getchar();
#endif
/* Shell can not handle large exit numbers -> 1 for errors */
if( ret < 0 )
ret = 1;
mbedtls_exit( ret );
}
#endif /* MBEDTLS_SSL_SRV_C && MBEDTLS_SSL_PROTO_DTLS &&
MBEDTLS_SSL_COOKIE_C && MBEDTLS_NET_C && MBEDTLS_ENTROPY_C &&
MBEDTLS_CTR_DRBG_C && MBEDTLS_X509_CRT_PARSE_C && MBEDTLS_RSA_C
&& MBEDTLS_CERTS_C && MBEDTLS_PEM_PARSE_C && MBEDTLS_TIMING_C */